Some criteria to minimize the impact of brine discharge into the sea

On a uniformly sloping beach, high salinity build-up along the coast associated with brine discharge into the sea can be avoided by building a longer outfall. For an existing seawater desalination plant, extending the outfall will affect the design specification of the plant. Using a two-dimensional advection–diffusion equation, model solutions that can minimize the shoreline salinity levels without building a longer sea outfall are presented.

Fig. 2. Reduction factor b for the slope step discontinuity depth profile with m0 = 0.1. By creating a jump discontinuity on the seabed depth profile, and keeping the outfall location in the deeper region, some criteria are presented that minimize the salt concentration levels along the beach due to continuous brine waste discharge into the sea. The results show that without building a longer sea outfall, the salt concentration levels along the beach can still be substantially reduced. A uniformly sloping beach is not the natural seabed depth profile. Due to beach erosion processes and coastal sediment transport, a jump discontinuity is formed on the depth profile. Dredging the seabed is a common coastal engineering practice to protect beaches from further erosion. As far as desalination plants are concerned, to deepen the water depth beyond the near shore region will also increase plant efficiency. The brine plumes could be rapidly dispersed and dissolved before they reach the intake location.